Field of the Invention
The invention relates generally to a system and method for determining a location of an interfering signal source.
Background Information
Signals which interfere with GNSS receivers, whether unintentional or intentional, may cause significant degradation in performance of such receivers and, in some cases, may represent a serious threat. Some interfering signal sources are simply electronic devices which, through poor design or malfunction, are accidentally transmitting on GNSS frequencies of interest (e.g., L1 or L2). Other interfering signal sources are specifically designed to cause interference. For example, while illegal to sell, possess or use in the US, Canada and UK, handheld GNSS “personal privacy devices” (i.e., jammers) are widely available and inexpensive. Such jammers typically operate at power levels of 200-300 milliwatts and claim to be effective for a range of 5-10 meters. However, such jammers may adversely affect GNSS receivers at a range of more than 1 kilometer.
Determining the position of a jammer in real-time or near real-time is a challenging problem. A jammer's signal is typically wideband in nature and resembles a pulse or chirp with a period that is likely not known by a party (e.g., law enforcement) attempting to determine the location of the jammer. In addition, although a jammer's operating frequency band may be known or ascertained, its precise operating frequency is likely not known. Also, a jammer may vary its operating frequency over time further complicating the problem of determining its location.